diff --git a/library/x509.c b/library/x509.c
index eb14720..2205400 100644
--- a/library/x509.c
+++ b/library/x509.c
@@ -702,7 +702,7 @@
 #define snprintf compat_snprintf
 #endif /* _MSC_VER && !snprintf && !EFIX64 && !EFI32 */
 
-#define MBEDTLS_ERR_DEBUG_BUF_TOO_SMALL    -2
+#define ERR_BUF_TOO_SMALL    -2
 
 #define SAFE_SNPRINTF()                             \
 {                                                   \
@@ -711,7 +711,7 @@
                                                     \
     if( (unsigned int) ret > n ) {                  \
         p[n - 1] = '\0';                            \
-        return( MBEDTLS_ERR_DEBUG_BUF_TOO_SMALL ); \
+        return( ERR_BUF_TOO_SMALL ); \
     }                                               \
                                                     \
     n -= (unsigned int) ret;                        \
@@ -870,7 +870,7 @@
     int ret;
 
     if( strlen( name ) + sizeof( " key size" ) > size )
-        return( MBEDTLS_ERR_DEBUG_BUF_TOO_SMALL );
+        return( ERR_BUF_TOO_SMALL );
 
     ret = mbedtls_snprintf( p, n, "%s key size", name );
     SAFE_SNPRINTF();